Beyond ordinary nutritional value, food can be supplemented with pharmaceutical or specialized nutritional additives to improve the health of a consuming human or animal. These additives can be intended to either be a regular e.g. daily part of a diet, or consumed intermittently, e.g. weekly or monthly.
One class of additive, probiotics, are live microbial organisms that beneficially affect animal or human hosts. Some known beneficial effects include improvement of the microbial balance of the intestinal microflora that aid digestion in higher animals. An example of a beneficial effect of probiotics is their use against specific groups of organisms, resulting in a decrease in numbers, by an effect on their metabolism or by stimulation of immunity. The introduction of a probiotic organism can suppress counts of an undesired organism by producing antibacterial compounds, by competing for nutrients or adhesion sites. Further, probiotics may alter microbial metabolism by increasing or decreasing enzyme activity or they may stimulate the immune system by increasing antibody levels or increasing macrophage activity.
While fatty acids, or lipids, can be provided in a variety of forms, some are more important than others. There are essential fatty acids that are not manufacturable by humans or some animals. Essential fatty acids fall into two groups: omega-3 and omega-6. The 3 and 6 refer to the first carbon double bond position on the fatty acid chain. All essential fatty acids are polyunsaturated, so the 3 and the 6 mean that the first double bond is either 3 or 6 carbons in from the end. Essential fatty acids include omega-6 fatty acids linoleic acid, arachidonic acid, gamma linolenic acid, dihomogamma linolenic acid, and the omega-3 fatty acids alpha linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid.
Omega-6 fatty acids are common: corn oil, sunflower oil and soybean oil all contain them. Omega-3 fatty acids are less common. Flax seeds, pumpkin seeds and walnuts are high in omega-3 fatty acids, as are salmon, trout and tuna. Current thinking is that these two fats need to be balanced in the diet at a ratio like 1-to-1 or 2-to-1, rather than the normal 20-to-1 ratio seen in most Western diets. Fatty fish like mackerel, lake trout, herring, sardines, albacore tuna and salmon are high in two kinds of omega-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid. Therefore, one way to achieve a proper balance is to supplement the diet with omega-3 fatty acid containing oils such as fish oils.
Fish oils can help humans to ameliorate or reverse atherosclerosis, angina, heart attack, congestive heart failure, arrhythmias, stroke, and peripheral vascular disease and may have other health benefits by helping to maintain the elasticity of artery walls, prevent blood clotting, reduce blood pressure and stabilize heart rhythm. Fish oils can also help animals maintain a healthy skin or coat.
Further, even simple mineral oils can aid the health of animals. For example, mineral oils can aid the passage of hairballs in cats through their digestive tracts.
Pharmaceutical and nutriceutical products intended for oral administration are typically provided in tablet, capsule, pill, lozenges and caplet form. These products are swallowed whole or chewed in the mouth for delivery of the active ingredient into the alimentary system of a body. Such oral delivery systems are sometimes made chewable to ease drug administration in pediatric and geriatric patients who may be uncooperative or particular about the form of nourishment they take. Concerns with ease of administration are also amplified when dealing with pets and other animals whose cooperation may be difficult to obtain. Accordingly, a food matrix that can not only contain pharmaceutical or nutriceutical products but also have acceptable appearance, texture, hardness, and other indicia of acceptability such as smell and taste are desirable.
In order to provide a food with a long shelf life, it is also desirable to regulate the water activity (aw) of a food. The water activity of a food is the ratio between the vapor pressure of the food itself, when in a completely undisturbed balance with the surrounding air media, and the vapor pressure of distilled water under identical conditions. A water activity of 0.80 means the vapor pressure is 80 percent of that of pure water. The water activity increases with temperature. The moisture condition of a product can be measured as the equilibrium relative humidity (ERH) expressed in percentage or as the water activity expressed as a decimal.
Most foods have a water activity above 0.95 and that will provide sufficient moisture to support the growth of bacteria, yeasts, and mold. The amount of available moisture can be reduced to a point which will inhibit the growth of the organisms. If the water activity of food is controlled to 0.85 or less in the finished product, it is not subject to the regulations of 21 CFR Parts 108, 113, and 114.
Water activity therefore affects food stability and therefore it must be brought to a suitable level at the conclusion of production and maintained within an acceptable range of activity values during storage.
As a result, several approaches have been utilized in the prior art in formulating oral delivery systems, including gums and candy bases. The use of such delivery systems is limited by the reaction of the active ingredient, whether it be pharmaceutical, nutriceutical or other ingredients, to the existence of water in the system, which can negatively impact shelf life, especially in the case of live probiotic material, which may undesirably multiply in the presence of moisture.
Accordingly, a food matrix that can deliver probiotic ingredients and contain high levels of oils while maintaining a low water activity level and a long shelf life are desirable to provide pharmaceutical and nutritional contributions to the health of animals.